Interplay between crystal structure, symmetry and topology in Kagome systems with different stackings

The 2-dimensional Kagome structure, with its pattern of corner-sharing triangles, hosts many interesting features related to frustrated magnetism, topology, and superconductivity. There is a growing attention on the transition-metal-based Kagome systems in the recent years. Bulk of the theoretical work so far focuses on 2D single-layer systems, and the out-of-plane interactions between Kagome layers are under less attention. In this talk, we present our results on the 3D tight-binding models and group theoretical analyses for 3D Kagome systems with different stacking ways that correspond to real materials, such as the the simple stacking (AV3Sb5) and the rhombohedral stacking (Co3S2Sn2). We compare the degeneracies and topological features, predict the effect of uniaxial stress (or strain), and provide materials-specific analyses using first-principles results.